Stackable container base



FIG. 1 is a top, left and front isometric view of a stackable container base showing my new design;

FIG. 2 is a bottom, left and rear isometric view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevation view, the rear elevation being identical thereto;

FIG. 6 is a left side elevation view, the right side elevation being identical thereto;

FIG. 7 is a cross-sectional view taken along line-7-7 of FIG. 3; and,

FIG. 8 is a cross-sectional view taken along line-8-8 of FIG. 3. 

CLAIM The ornamental design for a stackable container base, as shown and described. 